The present device is directed to an apparatus for retaining the working head of a wrench in a mounted position upon the nut or bolt head of a threaded bolt and nut combination. In its preferred form, the invention helps retain the working head of a wrench on either the nut or upon the bolt head so that the working head resists movement in a longitudinal direction along the bolt axis. The device according to this invention is constructed to be either a retrofit attachment for a wrench, but the apparatus could be manufactured with the wrench as a unit.
Many mechanics have experienced the problem of wrench head dislocation when using a wrench on a nut or bolt head. This is often experienced when a mechanic finds it necessary to place a pair of wrenches on a nut and bolt combination, one wrench being placed upon the bolt head and the other wrench being placed upon the nut. Should the nut and bolt head be located in areas of difficult access or should the head of the bolt and the nut be spaced a substantial distance apart, the mechanic often experiences the problem where the working head of one of the wrenches slips off of its respective work piece. In such situations, the mechanic often requires the assistance of a helper to hold one of the wrenches on its repective work piece while the mechanic operates the other wrench to either tighten or loosen the bolt and nut. This can be frustrating to the mechanic and lacks efficiency since two workers are required to perform a rather simple operation.
While some wrenches have been developed in the past which had as their objective the positioning of the working head of a wrench on a bolt, these devices were directed to preventing movement of the working head along the bolt axis in one direction. None of the prior art known to the inventor of the present invention developed structure which prevented movement of the working head in all directions along the axis of the bolt in order to releaseably lock the wrench head on the nut or bolt without requiring substantial and expensive modification of an existing wrench.
For example, U.S. Pat. No. 2,659,258 issued Nov. 17, 1953 to Dillard shows a bolt holding box wrench which is capable of retaining the working head of a wrench on a nut or a bolt head. This wrench requires substantial modification to an existing wrench structure or which requires special manufacture. In this patent, one or more elongated set screws are mounted in brackets on the shaft of a wrench and extend radially through the working head. By turning the set screws, the free end of the screw may be advanced to tighten onto a bolt head or nut located within the working head of the wrench.
U.S. Pat. No. 2,697,371 issued Dec. 21, 1954 to Bowman shows a wrench which is provided with a slideable plate so as to selectively mask a portion of the opening of the working head of a wrench so that the bolt head or nut will abutt this sliding plate to prevent movement in one direction along the axis of the bolt when the working head is positioned on a nut or bolt head. Accordingly, this patent shows a device that provides a moveable side wall for the opening in the working head. U.S. Pat. No. 1,550,436 issued Aug. 18, 1925 to Hall shows a somewhat similar structure to that of the Bowman patent in that it provides an auxillary wall which prevents movement of the wrench working head in one direction along a bolt once it has engaged a nut.
Despite these prior art patents and until the present invention, there remained a need for a simple device which could releasably retain a wrench, such as a box end wrench, on a work piece in the form of a nut or a bolt head. There was a further need for such a device to be simple in construction yet which could readily retrofit a wrench without the need for altering the wrench or undermining the integrity of the wrnech's working head.